Performance of strip-based glucose meters and cassette-based blood gas analyzer for monitoring glucose levels in a surgical intensive care setting.

BACKGROUND: We verified the analytical performance of strip-based handheld glucose meters (GM) for prescription use, in a comparative split-sample protocol using blood gas samples from a surgical intensive care unit (ICU). METHODS: Freestyle Precision Pro (Abbott), StatStrip Connectivity Meter (Nova), ACCU-CHEK Inform II (Roche) were evaluated for recovery/linearity, imprecision/repeatability. The GMs and the ABL90 (Radiometer) blood gas analyzer (BGA) were tested for relative accuracy vs. the comparator hexokinase glucose-6-phosphate-dehydrogenase (HK/G6PDH) assay on a Cobas c702 analyzer (Roche). RESULTS: Recovery of spiked glucose was linear up to 19.3 mmol/L (347 mg/dL) with a slope of 0.91-0.94 for all GMs. Repeatability estimated by pooling duplicate measurements on samples below (n=9), in (n=51) or above (n=80) the 4.2-5.9 mM (74-106 mg/dL) range were for Freestyle Precision Pro: 4.2%, 4.0%, 3.6%; StatStrip Connectivity Meter: 4.0%, 4.3%, 4.5%; and ACCU-CHEK Inform II: 1.4%, 2.5%, 3.5%. GMs were in agreement with the comparator method. The BGA outperformed the GMs, with a MARD of 3.9% compared to 6.5%, 5.8% and 4.4% for the FreeStyle, StatStrip and ACCU-CHEK, respectively. Zero % of the BGA results deviated more than the FDA 10% criterion as compared to 9.4%, 3.7% and 2.2% for the FreeStyle, StatStrip and ACCU-CHEK, respectively. For all GMs, icodextrin did not interfere. Variation in the putative influence factors hematocrit and O2 tension could not explain observed differences with the comparator method. CONCLUSIONS: GMs quantified blood glucose in whole blood at about the 10% total error criterion, proposed by the FDA for prescription use.

Performance of cassette-based blood gas analyzers to monitor blood glucose and lactate levels in a surgical intensive care setting.

BACKGROUND: With the use of a traditional blood gas analyzer (BGA) (ABL800 Radiometer) for blood glucose monitoring, tight glucose control (TGC) reduced in-hospital mortality and morbidity of surgical intensive care unit (ICU) adult and pediatric patients. Such BGAs are now superseded by cassette-based BGAs. We assessed the analytical reliability of cassette-based BGAs to monitor patient's metabolic status in an ICU setting. METHODS: We evaluated recovery/linearity, imprecision/repeatability and relative accuracy vs. comparison methods for glucose [coupled hexokinase glucose-6-phosphate dehydrogenase (HK/G6PD) assay] and lactate (lactate dehydrogenase assay) in ICU patient samples with two cassette-based BGAs [RP500 (Siemens) and ABL90 (Radiometer)] and with the ABL800 BGA. RESULTS: Recovery of spiked glucose up to 348 mg/dL (19.3 mmol/L) was complete for all BGAs. Repeatability of ABL800 and ABL90 was comparable with the comparison method (about 1%), but higher for RP500 (about 2.4%). All BGAs were in agreement with the comparison method, with all glucose measurements falling within preset 10% criteria suggested by Karon. Recovery of spiked lactate (up to 25 mmol/L) was incomplete at all levels. Repeatability of ABL800 and ABL90 was comparable with the comparison method (about 4%), and 5.5% for RP500. All BGAs were in agreement with the comparison method, with >98% of the lactate measurements falling within 30% biological-variation-based criteria. CONCLUSIONS: The cassette-based BGAs quantified blood glucose and lactate levels in ICU patients within the acceptable error ranges. Cassette-based BGAs can be used for monitoring patient's metabolic status in an ICU setting.